/*
 jQuery UI Sortable plugin wrapper

 @param [ui-sortable] {object} Options to pass to $.fn.sortable() merged onto ui.config
 */
angular.module('ui.sortable', [])
    .value('uiSortableConfig',{})
    .directive('uiSortable', [
      'uiSortableConfig', '$timeout', '$log',
      function(uiSortableConfig, $timeout, $log) {
        return {
          require: '?ngModel',
          scope: {
            ngModel: '=',
            uiSortable: '='
          },
          link: function(scope, element, attrs, ngModel) {
            var savedNodes;

            function combineCallbacks(first,second){
              if(second && (typeof second === 'function')) {
                return function() {
                  first.apply(this, arguments);
                  second.apply(this, arguments);
                };
              }
              return first;
            }

            function getSortableWidgetInstance(element) {
              // this is a fix to support jquery-ui prior to v1.11.x
              // otherwise we should be using `element.sortable('instance')`
              var data = element.data('ui-sortable');
              if (data && typeof data === 'object' && data.widgetFullName === 'ui-sortable') {
                return data;
              }
              return null;
            }

            function hasSortingHelper (element, ui) {
              var helperOption = element.sortable('option','helper');
              return helperOption === 'clone' || (typeof helperOption === 'function' && ui.item.sortable.isCustomHelperUsed());
            }

            // thanks jquery-ui
            function isFloating (item) {
              return (/left|right/).test(item.css('float')) || (/inline|table-cell/).test(item.css('display'));
            }

            function getElementScope(elementScopes, element) {
              var result = null;
              for (var i = 0; i < elementScopes.length; i++) {
                var x = elementScopes[i];
                if (x.element[0] === element[0]) {
                  result = x.scope;
                  break;
                }
              }
              return result;
            }

            function afterStop(e, ui) {
              ui.item.sortable._destroy();
            }

            var opts = {};

            // directive specific options
            var directiveOpts = {
              'ui-floating': undefined
            };

            var callbacks = {
              receive: null,
              remove:null,
              start:null,
              stop:null,
              update:null
            };

            var wrappers = {
              helper: null
            };

            angular.extend(opts, directiveOpts, uiSortableConfig, scope.uiSortable);

            if (!angular.element.fn || !angular.element.fn.jquery) {
              $log.error('ui.sortable: jQuery should be included before AngularJS!');
              return;
            }

            if (ngModel) {

              // When we add or remove elements, we need the sortable to 'refresh'
              // so it can find the new/removed elements.
              scope.$watch('ngModel.length', function() {
                // Timeout to let ng-repeat modify the DOM
                $timeout(function() {
                  // ensure that the jquery-ui-sortable widget instance
                  // is still bound to the directive's element
                  if (!!getSortableWidgetInstance(element)) {
                    element.sortable('refresh');
                  }
                }, 0, false);
              });

              callbacks.start = function(e, ui) {
                if (opts['ui-floating'] === 'auto') {
                  // since the drag has started, the element will be
                  // absolutely positioned, so we check its siblings
                  var siblings = ui.item.siblings();
                  var sortableWidgetInstance = getSortableWidgetInstance(angular.element(e.target));
                  sortableWidgetInstance.floating = isFloating(siblings);
                }

                // Save the starting position of dragged item
                ui.item.sortable = {
                  model: ngModel.$modelValue[ui.item.index()],
                  index: ui.item.index(),
                  source: ui.item.parent(),
                  sourceModel: ngModel.$modelValue,
                  cancel: function () {
                    ui.item.sortable._isCanceled = true;
                  },
                  isCanceled: function () {
                    return ui.item.sortable._isCanceled;
                  },
                  isCustomHelperUsed: function () {
                    return !!ui.item.sortable._isCustomHelperUsed;
                  },
                  _isCanceled: false,
                  _isCustomHelperUsed: ui.item.sortable._isCustomHelperUsed,
                  _destroy: function () {
                    angular.forEach(ui.item.sortable, function(value, key) {
                      ui.item.sortable[key] = undefined;
                    });
                  }
                };
              };

              callbacks.activate = function(e, ui) {
                // We need to make a copy of the current element's contents so
                // we can restore it after sortable has messed it up.
                // This is inside activate (instead of start) in order to save
                // both lists when dragging between connected lists.
                savedNodes = element.contents();

                // If this list has a placeholder (the connected lists won't),
                // don't inlcude it in saved nodes.
                var placeholder = element.sortable('option','placeholder');

                // placeholder.element will be a function if the placeholder, has
                // been created (placeholder will be an object).  If it hasn't
                // been created, either placeholder will be false if no
                // placeholder class was given or placeholder.element will be
                // undefined if a class was given (placeholder will be a string)
                if (placeholder && placeholder.element && typeof placeholder.element === 'function') {
                  var phElement = placeholder.element();
                  // workaround for jquery ui 1.9.x,
                  // not returning jquery collection
                  phElement = angular.element(phElement);

                  // exact match with the placeholder's class attribute to handle
                  // the case that multiple connected sortables exist and
                  // the placehoilder option equals the class of sortable items
                  var excludes = element.find('[class="' + phElement.attr('class') + '"]:not([ng-repeat], [data-ng-repeat])');

                  savedNodes = savedNodes.not(excludes);
                }

                // save the directive's scope so that it is accessible from ui.item.sortable
                var connectedSortables = ui.item.sortable._connectedSortables || [];

                connectedSortables.push({
                  element: element,
                  scope: scope
                });

                ui.item.sortable._connectedSortables = connectedSortables;
              };

              callbacks.update = function(e, ui) {
                // Save current drop position but only if this is not a second
                // update that happens when moving between lists because then
                // the value will be overwritten with the old value
                if(!ui.item.sortable.received) {
                  ui.item.sortable.dropindex = ui.item.index();
                  var droptarget = ui.item.parent();
                  ui.item.sortable.droptarget = droptarget;

                  var droptargetScope = getElementScope(ui.item.sortable._connectedSortables, droptarget);
                  ui.item.sortable.droptargetModel = droptargetScope.ngModel;

                  // Cancel the sort (let ng-repeat do the sort for us)
                  // Don't cancel if this is the received list because it has
                  // already been canceled in the other list, and trying to cancel
                  // here will mess up the DOM.
                  element.sortable('cancel');
                }

                // Put the nodes back exactly the way they started (this is very
                // important because ng-repeat uses comment elements to delineate
                // the start and stop of repeat sections and sortable doesn't
                // respect their order (even if we cancel, the order of the
                // comments are still messed up).
                if (hasSortingHelper(element, ui) && !ui.item.sortable.received &&
                    element.sortable( 'option', 'appendTo' ) === 'parent') {
                  // restore all the savedNodes except .ui-sortable-helper element
                  // (which is placed last). That way it will be garbage collected.
                  savedNodes = savedNodes.not(savedNodes.last());
                }
                savedNodes.appendTo(element);

                // If this is the target connected list then
                // it's safe to clear the restored nodes since:
                // update is currently running and
                // stop is not called for the target list.
                if(ui.item.sortable.received) {
                  savedNodes = null;
                }

                // If received is true (an item was dropped in from another list)
                // then we add the new item to this list otherwise wait until the
                // stop event where we will know if it was a sort or item was
                // moved here from another list
                if(ui.item.sortable.received && !ui.item.sortable.isCanceled()) {
                  scope.$apply(function () {
                    ngModel.$modelValue.splice(ui.item.sortable.dropindex, 0,
                        ui.item.sortable.moved);
                  });
                }
              };

              callbacks.stop = function(e, ui) {
                // If the received flag hasn't be set on the item, this is a
                // normal sort, if dropindex is set, the item was moved, so move
                // the items in the list.
                if(!ui.item.sortable.received &&
                    ('dropindex' in ui.item.sortable) &&
                    !ui.item.sortable.isCanceled()) {

                  scope.$apply(function () {
                    ngModel.$modelValue.splice(
                        ui.item.sortable.dropindex, 0,
                        ngModel.$modelValue.splice(ui.item.sortable.index, 1)[0]);
                  });
                } else {
                  // if the item was not moved, then restore the elements
                  // so that the ngRepeat's comment are correct.
                  if ((!('dropindex' in ui.item.sortable) || ui.item.sortable.isCanceled()) &&
                      !hasSortingHelper(element, ui)) {
                    savedNodes.appendTo(element);
                  }
                }

                // It's now safe to clear the savedNodes
                // since stop is the last callback.
                savedNodes = null;
              };

              callbacks.receive = function(e, ui) {
                // An item was dropped here from another list, set a flag on the
                // item.
                ui.item.sortable.received = true;
              };

              callbacks.remove = function(e, ui) {
                // Workaround for a problem observed in nested connected lists.
                // There should be an 'update' event before 'remove' when moving
                // elements. If the event did not fire, cancel sorting.
                if (!('dropindex' in ui.item.sortable)) {
                  element.sortable('cancel');
                  ui.item.sortable.cancel();
                }

                // Remove the item from this list's model and copy data into item,
                // so the next list can retrive it
                if (!ui.item.sortable.isCanceled()) {
                  scope.$apply(function () {
                    ui.item.sortable.moved = ngModel.$modelValue.splice(
                        ui.item.sortable.index, 1)[0];
                  });
                }
              };

              wrappers.helper = function (inner) {
                if (inner && typeof inner === 'function') {
                  return function (e, item) {
                    var innerResult = inner.apply(this, arguments);
                    item.sortable._isCustomHelperUsed = item !== innerResult;
                    return innerResult;
                  };
                }
                return inner;
              };

              scope.$watch('uiSortable', function(newVal /*, oldVal*/) {
                // ensure that the jquery-ui-sortable widget instance
                // is still bound to the directive's element
                var sortableWidgetInstance = getSortableWidgetInstance(element);
                if (!!sortableWidgetInstance) {
                  angular.forEach(newVal, function(value, key) {
                    // if it's a custom option of the directive,
                    // handle it approprietly
                    if (key in directiveOpts) {
                      if (key === 'ui-floating' && (value === false || value === true)) {
                        sortableWidgetInstance.floating = value;
                      }

                      opts[key] = value;
                      return;
                    }

                    if (callbacks[key]) {
                      if( key === 'stop' ){
                        // call apply after stop
                        value = combineCallbacks(
                            value, function() { scope.$apply(); });

                        value = combineCallbacks(value, afterStop);
                      }
                      // wrap the callback
                      value = combineCallbacks(callbacks[key], value);
                    } else if (wrappers[key]) {
                      value = wrappers[key](value);
                    }

                    opts[key] = value;
                    element.sortable('option', key, value);
                  });
                }
              }, true);

              angular.forEach(callbacks, function(value, key) {
                opts[key] = combineCallbacks(value, opts[key]);
                if( key === 'stop' ){
                  opts[key] = combineCallbacks(opts[key], afterStop);
                }
              });

            } else {
              $log.info('ui.sortable: ngModel not provided!', element);
            }

            // Create sortable
            element.sortable(opts);
          }
        };
      }
    ]);
